Assessment Synopsis. – Cladonia submitis is a large conspicuous fruticose lichen that primarily occurs on coastal dunes and inland sandy soils along the Mid-Atlantic Coast of the eastern United States. Although often locally abundant where it occurs, the core range and habitats of the species have been severely fragmented and degraded. As with other dune inhabiting organisms, the species would benefit from legislative protection, dune/coastal conservation and restoration efforts, increased acquisition and protection of remaining coastal habitats, and long term monitoring of selected subpopulations to determine trend and demographics.

Distinguishing Traits. – The species is a large yellowish fruticose Cladonia that can be recognized by its thick, coarsely branched podetia that are roughened near the center of the thallus, and the tendency of the branches to appear combed or otherwise +/- prostrate and creeping along the ground.

TECHNICAL ASSESSMENT

Distribution and Ecology. – Cladonia submitis is endemic to eastern North America where it occurs on sandy soils, primarily in coastal dune habitats or inland sandy openings, in the Atlantic Coastal Plain from Massachusetts to Delaware. Many small, scattered disjunct populations occur in exposed rocky habitats at middle and low elevations of the central Appalachian Mountains from Maine south to West Virginia. The species is often locally abundant at sites where it occurs in the Atlantic Coastal Plain Barrens (i.e., Cape Cod, Long Island, and southern New Jersey). Nonetheless more than >50% of extant locations are isolated and small in size, thus the population of the species is fragmented. The species reproduces primarily asexually via thallus fragments, thus it is expected that the species is dispersal limited.
Brodo et al. (2001) mapped the species as occurring along the Atlantic Coast from Maine to South Carolina, however no vouchers were seen from any area south of Delaware along the coast and thus the published map is considered to be in error (note Brodo et al. (2001) also excluded disjunct inland locations from their map, which have been recognized and documented since the 1930’s). Ahti (1961) cited a possible specimen from Florida, however it could not be located and is presumed to have been misidentified. Any specimens identified as Cladonia submitis from the southeastern Coastal Plain outside of the range mapped herein are likely misidentifications of the superficially similar species C. pachycladodes Vain., as has been shown by review of material of the latter species at NY. Similarly specimens cited in CNALH and identified as C. submitis from high elevations of the southern Appalachians, Great Lakes, and Quebec are excluded as presumed misidentifications of the morphologically and chemically distinct species C. mitis Sandst.
In addition to North American locations, Cladonia submitis has been reported from coastal Japan and eastern Russia. However individuals from these locations are reported to differ morphologically from C. submitis (see Ahti 1961). Pending additional study of the eastern Asian populations, they are excluded from the concept of C. submitis employed here. It should be noted however, that if they were included the majority of reports are historical and the species would likely still be considered threatened or endangered.
Status of Populations – Within the core range of the Atlantic Coastal Pine Barrens, although many historical populations have not been relocated, additional new populations have been found that are presumed extant. In this region there are many populations located in protected areas, although the species also doubtless occurs in suitable habitat outside of protected management units. The disjunct populations that occur outside of the Coastal Plain are mostly not in protected management units, and often consist of small numbers of individuals in small open habitats that are geographically isolated amid much larger forested areas.

Protected Status. – None.

Threats. – There are two primary threats to this species. The first is habitat loss, degradation and fragmentation that have occurred historically at very large scales, continue at present to a more limited degree, and will likely continue into the future. Coastal dune habitats and adjacent inland sandy forests within the Mid-Atlantic region have been particularly altered by development and urbanization, and there is pressure will continue into the foreseeable future. The second major threat to this species stems from loss of habitat and habitat degradation associated with sea-level rise and other climate change related phenomena (e.g., storm-surges, coastal erosion, creation of artificial coastal barriers).

Explanation of Proposed Rank. – Cladonia submitis meets the criteria for ranking as Vulnerable A2c based on the documented declines in AOO, EOO and number of locations (pre- and post-1990) as well as the continued decline of suitable habitat due to a host of features (e.g., invasive species, resource extraction, large catastrophic forest-fires, visitation/use for recreation including A.T.V.s) as well as by development (urbanization and suburbanization, including the Boston-New York-Philadelphia-Washington D.C. metro region).

Conservation Recommendations. – Formal listing under state law and the Endangered Species Act together with inclusion of the species in dune restoration/coastal management plans is essential for maintaining and improving its conservation status. Increased acquisition and protection of remaining undeveloped coastal areas to assure continued existence of remaining populations is also needed. The species should also be taken into consideration for coastal habitat mitigation plans associated with sea-level rise and climate change.

Cladonia submitis is endemic to a small region of the Atlantic Coast of the United States where it faces a diverse array of threats.

Geographic range

Cladonia submitis is restricted to a small area of the the Atlantic Coast of the eastern United States, primarily between Cape Cod in Massachusetts and Virginia Beach in Virginia. The core range of the species is the Atlantic Coastal Pine Barrens of southern New Jersey and Long Island in New York. A small number of disjunct populations occur with other typically coastal Cladonia species at scattered inland locations of the central Appalachian Mountains. Care should be taken to distinguish between modern accounts of the distribution of this species and those from the historical literature where it was often confused with the chemically similar C. mitis.

Population and Trends

Demographic studies are needed to assess and monitor populations sizes. Our current knowledge of the species suggests that its populations are stable.

Threats

Threats to this species include ongoing impacts from extensive conversion of natural habitats in coastal areas of the Mid-Atlantic, both historical and modern. Loss of habitat and habitat degradation from development (residential, commercial and industrial), construction/maintenance of of roads and utility lines, and large scale recreation are primary threats to this species. Addition threats include competition from invasive plants, air pollution, climate change, and sea-level rise.

Conservation Actions

Many populations of this species occur within protected areas, however measures are required to assure that recreation and other activities do not negatively impact this species. Additional actions that can be taken including controlling invasive dune species, educating and training land managers and local botanists to identify the species so we can monitor its health, federally listing the species as endangered in the United States, improving air quality regulation, and establishing further conservation areas where the species occurs.

Research needed

The distribution of this species is very well understood. Further research that will aid in the conservation of this species includes population assessments and monitoring, population genetics studies, and ecological studies that incorporate threats to the species. Additionally, a species recovery plan needs to be written.